The Company’s 2018 Stock Option and Incentive Plan, (the “2018 Plan”), which became effective on March 27, 2018 provides for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock units, restricted stock awards, unrestricted stock awards, cash-based awards and dividend equivalent rights. The number of shares initially reserved for issuance under the 2018 Plan is 2,800,721. Additionally, the shares of common stock that remained available for issuance under the previously outstanding 2015 Stock Incentive Plan (the “2015 Plan”) became available under the 2018 Plan. The number of shares reserved for the 2018 Plan will automatically increase on each January 1 by 4% of the number of shares of the Company’s common stock outstanding on the immediately preceding December 31 or a lesser number of shares determined by the Company’s board of directors. The shares of common stock underlying any awards that are forfeited, canceled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, repurchased or are otherwise terminated by the Company under the 2018 Plan or the 2015 Plan will be added back to the shares of common stock available for issuance under the 2018 Plan. The number of authorized shares reserved for issuance under the 2018 Plan was increased by 1,202,319 shares effective as of January 1, 2019. As of September 30, 2019, 2,372,248 shares remained available for future issuance under the 2018 Plan.

The Company’s 2018 Employee Stock Purchase Plan (the “ESPP”) became effective on March 28, 2018 at which time a total of 314,000 shares of common stock were reserved for issuance. In addition, the number of shares of common stock that may be issued under the ESPP will automatically increase on each January 1 through January 1, 2027, by the least of (i) 500,000 shares of common stock, (ii) 1% of the number of shares of the Company’s common stock outstanding on the immediately preceding December 31 or (iii) such lesser number of shares as determined by the ESPP administrator. The number of authorized shares reserved for issuance under the ESPP was increased by 300,580 shares effective as of January 1, 2019. The first six month offering period was initiated on July 1, 2019. As of September 30, 2019, no shares have been issued under the ESPP and 614,580 shares remain available for issuance.

During the nine months ended September 30, 2019, the Company granted service-based options to participants for the purchase of 1,665,418 shares of common stock with a weighted average grant-date fair value of $2.25 per share.

During the nine months ended September 30, 2019, the Company granted options to certain employees for the purchase of 635,000 shares of common stock with a weighted average grant-date fair value of $2.46 per share that vest under a combination of performance-based and service-based vesting conditions if certain performance vesting criteria are achieved on or before March 31, 2020. As of September 30, 2019, the Company has not recorded stock-based compensation expense as the performance conditions have not been deemed to be probable of being achieved.

The Company recorded stock-based compensation expense in the following expense categories of its consolidated statements of operations and comprehensive loss (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Research and development expenses	$	505	$	629	$	1,692	$	1,637
General and administrative expenses		283		231		707		549
Total	$	788	$	860	$	2,399	$	2,186